Lathe control mechanism



June 26, 1951 Filed June 21, 1949 H. J. SIEKMANN EI'AL LATHE CONTROL MECHANISM 3 Sheets-Sheet 1 INVENTORS. HAROLD J. s/s/(m/vm HARRY c. KEMPER BY NEL so 0. COOPER A TTOR/VE).

June 26, 1951 H. J. SIEKMANN EIAL 2,558,275

LATHE CONTROL MECHANISM Filed June 21, 1949 3 Sheets-Sheet 2 INVENTORS.

meow .1. SIS/(MANN,

HARRY c. KE'MPER, BY NELSON 0. COOPER ATTORNE).

June 26, 1951 H. J. SIEKMANN ETAL 2,558,275

LATHE CONTROL MECHANISM Filed June 21, 1949 3 Sheet s$heet 3 IN V EN TORS- HAROLD J. SlEKMA/WV,

BY HARRY C. KEMPER, 4 NELSON COOPER A TTORNEY.

Patented June 26, 1951- 2,558,275 LATHE CONTROL MECHANISM Harold J. Slekmann, Cincinnati, Harry Kemper, Goshen Township, Clermont County, and Nelson D. Cooper,

orslcs to The R. K. Le Blond Machine Tool Company,

Cincinnati, Ohi

o, a corporation of Delaware Application June 21, 1949, Serial No. 100,342 9 Claims. (Cl. 82-2) This invention pertains to improvements in control for machine tools and is particularly directed to improvements in lathe control mech-- anism.

2 the rear of the lathe bed HI and having guideslides the rear tool slide 25 One of the objects of this invention is to pro- The work spindle of the lathe is driven from vide electric control mechanism and a control cirthe main drive motor 29 which has a pulley 30 cult for effecting an automatic cycle of operation on its shaft over which operates the belts 3| for a lathe. which in turn drive the clutch pulley 32 suitably Another object of this invention is to provide journaled on the headstock IS. A conventional an electric control apparatus for a lathe in which multiple-disc clutch 33 serves to connect or disthe feed and rapid traverse movements of the connect power from the constantly operating cutting tool are controlled by the interaction main drive motor to the input shaft 34 of the between the lathe carriage and apron and an headstock transmission of the lathe. The clutch axially reciprocatable feed and rapid traverse is operated by the push rod 35 having a spool 3 drive rod and trip bar. fixed thereto and engaged by the spindle start Still another object is to provide in a lathe and stop lever 31 pivotally mounted on the headcontrol mechanism a novel tool relief mechanism s ock on a suitable shaft ll. When the lever is for the cross slide of the lathe which is operated in the stop' position 310 h wn in i ur 2, the in timed relationship with the longitudinal moveclu ch 33 is d ng and Wh n th l ver is i ment of the carriage. 2 the "run position 31b, the clutch is engaged to It is also an object to provide interlock mechapp y h d ive o or 9 to rota e the Work anism between the feed mechanism of the lathe p ow f m he nput haft 3 of th and the spindle stop and start control mechheadstock y be connected, at different rates of anism of the machine so that the feed and speed to the work spindle 28 in a well known spindle rotation are operated in a predetermined manner, as by the v o s li ing change a s relationship. indicated generally at 39, 40 and 4|, so as to Further features and advantages 'of this inventat th sp ndle at h desir d u t n p edtion will appear from the detailed description of w r for dri in h ol id s 20 and 2 at the drawings in which; feeding rates is derived from the work spindle,

Figure 1 is a front perspective view of a lathe P w being taken 01? om a pr c fixed incorporating the features of this invention. to the spindle which drives the chain 43 which Figure 2 is, a diagram showing th operating in turn connects with the sprocket 44 on the inand control mechanism of the lathe shown in termediate shaft 4 ri d in h f d box I A Figure 1. gear 46 is connected in driving relationship with Figure 3 is an electric circuit diagram used in the prock t and in urn driv he ar conjunction with th lath fixed on the input shaft 48 of the feed box ll.

Figure 4 is a diagram showing t path of Aseriesof shiftable gear sets indicated generally movements of the cutting tools during an t at 49 provides different feed rates to the output matic operating cycle of the machine. ft 50 of the f ed box.

A ill tr ti of a machine t t which this Coaxially positioned with the output shaft 50 invention is particularly well adapted. there is of the feed box is the rotatable and axially hown i Figure 1 a typical type of lathe known reciprocatable feed and rapid traverse drive rod as a rapid production lathe comprising a bed In or shaft 5! hevmg a clutch spool 52 fi d o i mounted on the legs II and I2 and having longileft ha d e d, igures 1 and 2, which has clutch tudinally extending bed ways l3 upon which 15 teeth 53 adapted to n a e ating clutch teeth reciprocatably mounted the carriage I 4 Also 54 carried on the end of the output shaft of carried on the bed I0 is the headstock ii, the the d X n e rOd s'mov d to its left tailstock l6, and the feed box l1.- Depending position. The clutch teeth 5354 comprise the downwardly from the front of the carriage is the feed clutch mechanism of the lathe. The rod apron l8 and reciprobatably mounted for trans- 50 passes through the apron II and the driving verse movement on the guideways IS on the carbevel pinion 55 ournaled in the apron against rlage is the cross slide 20. The cross slide carries axial movement The bevel pinion has a keyed the usual tool post 2| and the cutting tool 22 driving bore 56 so that the drive rod 5| The lathe may also have a rear tool slide or facmay slide through it and at the same time drive ing attachment comprising a bracket 23 fixed to 55 the apron mechanism during the movement of the apron and carriage along the bed. The driving bevel gear 55 drives the usual apron gearing shown diagrammatically as the bevel gear 51 which is connected to the gear 58 which in turn drives the gearing 59 and 00, and the gear 6| on the rack pinion shaft 62 upon which is the rack pinion 63 which engages the rack 1 fixed on the bed I0 of the lathe. In this way rotation of the drive rod effects longitudinal movement of the carriage along the bed. Manual actuation of the carriage may be had by the usual hand wheel 65 on thehandwheel shaft 66 having the pinion 8? in engagement with the gear 6| on the rack pinion shaft 62.

The right hand end of the drive rod 5!, Figures 1 and 2, is journaled for rotation and axial reciprocation in the bushing 68 fixed in the end box 69 fixed to the right hand end of the bed of the lathe. Journaled against axial movement on the outside surface 68a of the bushing 58 is the cup member of the rapid traverse clutch indicated generally at I I. The cup member is constantly driven from the continuously operating rapid traverse motor I2 mounted on the right hand end of the lathe bed and having a sprocket I3 driving a chain I4 connected to the sprocket I5 formed on the cup member I0. Fixed on the rod 5| is the mating cone member 16 of the rapid traverse clutch 1|. An annular groove or spool is provided at I! on the cone member which is engaged by a lever I8 connected to the length traverse solenoid LTS suitably mounted on the machine frame so that when this solenoid is energized the cone member I6 and the rod 5| are moved to extreme right position to connect the rapid traverse drive from the motor I2 to rapidly rotate the rod 5|.

Power take off for both feed and rapid traverse movements to the rear tool slide 25 may be had from the sprocket I9 formed on the cone member I6 through the chain 80 and the sprocket 8| on the input shaft 82 of the rear tool slide transmission indicated generally at 83, this transmission comprising suitable gearing 84, 85, and 86, the cam drum 8'1, and the roller 88 fixed on the tool slide 25 to efiect the transverse movements for the tool 21.

The feed clutch 53-54 is engaged and disengaged, when solenoid LTS is de-energized, by the operation of a reciprocatable trip bar 80 which is suitably mounted on supports 00 and 9| for longitudinal movement on the front of the lathe bed just below the apron I8. A tension spring 92 between a pin 93 fixed to the machine frame and a pin 04 fixed to the trip bar, causes the bar to be normally urged to the right, Figures 1 and 2. On the left hand end of the trip bar is fixed the block 95 by suitable rivets 98. g A threaded stud 91 is fixed in the block and passes through the clearance hole 98 in a lug Ila formed integral with the feed box II. Stop nuts 50 and I00 engage each side IM and I02 respectively of the lug to accurately limit movement of the trip bar 89. The trip bar is connected to oppositely reciprocate the feed and rapid traverse rod 5| through a lever I03 pivotally mounted on the machine frame on a stud I04 pivotally connected at one end to the block 95 by a pin I05. The other end of the lever is received in the annular groove I06 formed in the clutch spool 52 on the rod 5i Pivotaliy mounted on the stud 07 fixed in the apron I8 is the trip dog lever I108 which is adapted for swinging movement in a vertical plane 09. The lever has 2. depending trip finger I I0 with an abutment face III adapted to engage the trip dog I12 adiustably clamped on the trip bar 88 as the carriage and apron feed toward the headstock of the lathe. When it is desired to operate the longitudinal movement of the carriage manually by the handwheel 65 without actuating the trip bar, the operator holds up on the lever keeping it in its upper position I082) from the normal position I080, so the trip finger will be rocked forward and will clear the trip dog i i2.

Interlock mechanism is provided between the spindle start and stop lever 31 and the trip bar 89 so that the trip bar is normally held in feed disconnected position when the spindle is stopped. This mechanism comprises a bell crank lever I I3, Figure 2, pivotally mounted on a suitable pin I I4 carried on the machine frame and connected by a link H5 to the lever 31 and connected to the push rod II6 which has a yielding connection ill with the latch member H8. When the lever 3? is in stop position 31a the trip bar is held in feed disengaged position by the latch pin member H8 extending down along the right side II9 of the latch dog I20 adjustably clamped on the trip bar. The yielding connection Ill enables the operator to at any time manually move the spindle control lever 3'1 to stop position even though the end I2I of the latch pin is on the top surface I22 of the latch dog I20 when the feed clutch 53-54 is engaged. Also under these conditions the operator may latch out the feed clutch 53-54 by moving the carriage to the left till the trip finger IIO engages the dog H2 and moves the trip bar till the latch plunger drops down, under the influence of the yielding connection I ll, behind the face of the dog I20, the spindle control lever being in the stop position 31a at this time.

The cross slide 20 is actuated to predetermined in and out" positions of cutting and tool relief respectively on the carriage by a reversable cross feed motor I23 which is mounted on the lathe apron I8. This motor is arranged to drive an axially reciprocatable worm shaft I24 carried by the apron and carriage through a suitable sliding driving connection I25. A worm I28 is fixed on the shaft I24 and is normally yieldingly held axially in an intermediate'position by the compression springs I21 and I28 which react against suitable abutment surfaces I29 of the lathe carriage. The worm I26 is in engagement with a worm wheel I30 fixed on the usual cross feed screw I3I of the lathe which operates in the cross feed nut I32 fixed to the tool slide 20. Adjustable stop abutments, such as the screws I33 and I34, are provided on the lathe carriage to engage the respective abutment surfaces I35 and I36 of the cross slide 20 to limit its movement to definite predetermined in" and out" positions.

Fixed to the worm shaft I24 is the spool I31 which is engaged by a T-shaped lever I38 pivotally mounted on a suitable pin I39 carried in the lathe carriage. Each of the extending arms I304; and |38b of the lever are arranged to respectively engage and operate the limit switches LS2 and LS-l as the worm shaft is reciprocated axially upon engagement of the cross slide with either of the abutment screws I33 or I34 which causes one or the other of the springs I21 and I28 to yield when the rotation of the worm wheel and cross feed is stopped.

Operation L2, and L-9 to the operating circuit. The selector switch MI .is set to on" position so as to interconnect leads I42 and I43. The start push button I44 is then pressed so as to connect spindle motor relay coil S with the lead I45 of the secondary winding I46 of the pilot circuit transformer I41, through the normally closed stop push button I48 to the other lead I49 of the secondary winding of the transformer. In thus energizing coil S contacts So are closed connecting power to the spindle motor 29. At the same time the holding contact Sb closes to maintain this circuit after the start" button I44 has been released. At the same time the length traverse motor 12 is energized by connecting the length traverse relay coil LT through leads I42, selector switch MI, and lead I43 to the lead I49. This closes contacts LTa starting the length traverse motor I2 and also closes the control contact LTb which connects lead I42 wiht lead I50 to bring the remaining part of the control circuit into operation. During the normal automatic operation the spindle motor 29 and the length traverse motor "I2 run continuously. In instances where coolant is required a coolant pump motor I5I may be cut into the circuit by pressing the selector switch I52 to on position.

The work spindle 28 is started for rotation of a workpiece W, Figure 4, by manually moving the spindle control lever to run Figure 2, engaging the clutch 33 to connect driving power from the motor 29. A spindle stop solenoid SS mounted on the frame or headstock of the lathe has an armature I53 connected by a link I54 to the lever 31 so that when energized it moves the lever to stop position 31a. A dog I55 on the armature of the solenoid SS engages and closes the limit switch LS-B when the spindle control lever is moved to start or run position 31?). Closing of limit switch LS6 connects lead I42, through the normally closed contact 'I'Ra of the timer relay TR through the coolant pump motor relay coil GP to the lead I49. This closes contacts CPa to energize the coolant pump motor I5I.

When the spindle controllever is in'the stop position 3111 the feed clutch 5354 is held in disengaged poistion but when the lever is moved to the run position 311) the latch pin H8 is withdrawn from the dog I20 and the clutch 53-35 54 springs into engagement under the influence of the spring 92. The longitudinal movement of the trip bar to the right at this time causes a dog I56 carried on the trip bar to operate the limit switch LSI closing the circuit from lead I 58 through the normally closed limit switch LS 2 and the cross feed motor I23 to the lead I49. Thus the cross feed motion and the longitudinal feed motion are taking place simultaneously as indicated by the diagonal line of tool travel I58 in Figure 4 to bring the cutting tool 22 into operating position I 59 from the starting position I69.

The in feed of the tool slide 20 is stopped when it engages the stop screw I33 which causes the worm shaft I24 to shift axially to open limit switch 15-2 to de-energize the cross feed motor I23 so the cross slide 29 remains in cutting position against the set screw I33 as the longitudinal feed motion continues along the line I6l, Figure 4. The longitudinal feeding of the carriage continues until the trip finger IIII on the apron engages the dog II2 to shift the trip bar to the left to disengage the feed clutch 53-54 with the cutting tool at the point I62, Figure 4. A dog I51 on the trip bar 89 closes limit switch LS-3 position 31b,

, shown at I64 in Figure 4.

6 which connects lead I50 through the timing relay coil TR to the lead I49. This causes an Immediate closing of the contact 'IRb to complete a circuit from lead I50 throughthe normally closed limit switch 1-8-4 and the cross feed motor I23 to the lead I49 to start this motor in the opposite direction to withdraw the cross slide outwardly from the work as indicated by the line I63, Figure 4. This out feed motion of the cross slide 20 continues until it engages the stop screw I34 which causes the shifting of the worm shaft I23 and the opening of the limit switch LS4 which de-energizes the motor I 23 to hold the cross slide in the out or tool relief position After a predetermined time delay or dwell at the position I64 has taken place by the timer portion TRy, indicated in broken line in igure 3, of the timer relay TR, the timer contact TRa opens to cut off the coolant pump motor and the timer contact TRc closes connecting lead I50 through the normally closed limit switch 18-6 to lead I58 connected to the long'tudinal rapid traverse relay coil LTSR and to the spindle stop relay coil SSR, both of which coils are connected to the lead I 49. Energizing coil LTSR closes contacts LTSRa. which energizes solenoid LTS to move the drive rod 5| still further to the right in feed disengaged direction to engage the rapid traverse clutch II to rapidly rotate the rod SI for quick return of the carriage and apron to the right along line I65, Figure 4, to starting position I60. Energizing coil SSR closes contacts SSRa which energizes solenoid SS which moves the spindle control lever 31 back to stop position 31a to stop work spindle rotation. It will be noted that whenever the lever is moved to stop" position 37a the limit switch LS6 is opened so as to shut off coolant when the spindle is stopped. The rear cutting tool 2'! follows the path indicated by the line I66 in Figure 4, moving from the starting position I61 to end of cut at I68 at feed and returning at rapid traverse to the starting position.

When the carriage reaches the end of its right hand travel and arrives at the starting position, a limit switch LS-5, which is adjustably clamped to the bed ways I3 for any desired starting position .for the carriage, is engaged by the carriage so as to open to de-energize both coils LTSR and SSH. to respectively de-energize the solenoid LTS to stop the traverse movement of the carriage and the solenoid SS so as to free the spindle control lever for manual operation to start the next operating cycle. For manual operation without the automatic cycle, the selector switch I is set to oil position so that only the spindle motor is put in operation with the remainder of the electric circuit de-energized.

Having thus fully set forth and described this invention, what is claimed is:

1. In a control mechanism for a lathe having v a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed, and a feed box on the left hand end of said bed and driven from said headstock, an output shaft in saidfeed box, an axially reciprocatable drive rod extending longitudinally of s aid bed, means for connecting said drive rod to gearing in said apron to efiect longitudinal movement of the carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and means for engaging said feed clutch means by the axial movement of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, means interconnecting said drive rod and said trip bar for opposite reciprocatory movement means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to effect movement of said drive rod away from said feed box to discharge said feed clutch means and arrest longitudinal feeding movement of said carriage, a rapid traverse drive motor, rapid traverse clutch means between said rapid traverse drive motor and said drive rod, and means for axially moving said drive rod further in feed disengaged direction to the right to engage said rapid traverse clutch means to effect rapid longitudinal movement of said carriage in the opposite direction in rapid return movement from said feed movement.

2. In a control mechanism for a lathe having a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed, and a feed box on the left hand end of said bed and driven from saidheadstock, an output shaft in said feed box, an axially reciprocatable drive rod extending longitudinally of said bed, means for connecting said drive rod to gearing in said apron to eifect longitudinal movement of the carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and means for engaging said feed clutch means by the axial movement'of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, means interconnecting said drive rod and said trip bar for opposite reciprocatory movement, means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to effect movement of said drive rod away from said feed box to disengage said feed clutch means and arrest longitudinal feeding movement of said carriage, a rapid traverse drive motor, rapid traverse clutch means between said rapid traverse drive motor and said drive rod, and means for axially moving said drive rod further in feed disengaged direction to the right to engage said rapid traverse clutch means to effect rapid longitudinal movement of said carriage in the opposite direction in rapid return movement from said feed movement, said means for further axially moving said drive rod to engage said rapid traverse clutch means including electrically actuated means, and electrical control means operated by the movement of said trip bar to feed disengaged position to energize said electrically actuated means.

3. In a control mechanism for a lathe having a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed, and a feed box on the left hand end of said bed and driven from said headstock, an output shaft in said feed box, an axially reciprocatable drive rod extending longitudinally of said bed, means for connecting said drive rod to gearing in said apron to effect longitudinal movement of the carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and means for engaging said feed clutch means by the axial movement of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, means interconnecting said drive rod and said trip bar for opposite reciprocatory movement, means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to effect movement of said drive rod away from said feed box to disengage said feed clutch means and arrest longitudinal feeding movement of said carriage, a rapid traverse drive motor, rapid traverse clutch means between said rapid traverse drive motor and said drive rod, and means for axially moving said drive rod further in feed disengaged direction to the right to engage said rapid traverse clutch means to effect rapid longitudinal movement of said carriage in the opposite direction in rapid return movement from said feed movement, said means for further axially moving said drive rod to engage said rapid traverse clutch means including electrically actuated means, and electrical control means operated by the movement of said trip bar to'feed disengaged position to energize said electrically actuated means, and further electrical control means operated by the movement of said carriage in rapid return movement to a predetermined position to de-energize said electrically actuated means to arrest movement of said carriage.

4. In a control for a lathe having a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed and a feed box on the left hand end of said bed and driven from said headstock, an output shaft in said feed box, an axially reciprocatable drive rod extending longitudinally of said bed, means for connecting said drive rod to gearing in said apron to effect longitudinal movement of the carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and means for engaging said feed clutch means by the axial movement of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, means interconnecting said drive rod and said trip bar for opposite reciprocatory movement, means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to effect movement of said drive rod away from said feed box to disengage said feed clutch means and arrest longitudinal feeding movement of said carriage, a rapid traverse drive motor, rapid traverse clutch means betweensaid rapid traverse drive motor and said drive rod, and means for axially moving said drive rod further in feed disengaging direction to the right to engage said rapid traverse clutch means to effect rapid longitudinal movement of said carriage in the opposite direction in rapid return movement from said feed movement, said means for further axially moving said drive rod to engage said rapid traverse clutch means including electrically actuated means, and electrical control means operated by the movement of said trip'bar to feed disengaged position to energize said electrically actuated means, and further electrical control means operated by the movement of said carriage in rapid return movement to a predetermined position to de-energize said electrically actuated means to arrest movement of said carriage, and render said main drive motor ineffective to drive said headstock transmission.

5. In control apparatus for a lathe having a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed, and a feed box on the left hand end of said bed and driven from said headstock, an output shaft in said feed box, an axially reciprocatable drive rod extending longitudinally of said bed, means for connecting said drive rod to gearing in said apron to eilect longitudinal movement of said carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and'means for engaging said clutch means by the axial movement of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, meansinterconnecting said drive rod and said trip bar for opposite reciprocatory movement, means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to eifect movement of said drive rod away from said feed box to disengage said feed clutch and arrest longitudinal feeding movement of said carriage, means for connecting or disconnecting said main drive relative to said headstock transmission including a spindle control lever having a stop and run position for the work spindle of said headstock transmission, and an interlock mechanism between said spindle control lever and said trip bar arranged to hold said trip bar and drive rod in feed disengaged position when said spindle con- .trol lever is in the stop position.

6. In a control mechanism for a lathe having a bed, a headstock having a headstock transmission, a main drive motor for driving said headstock transmission, a carriage and apron longitudinally reciprocatable on said bed, and a feed box on the left hand end of said bed and driven from said headstock, an output shaft in said feed box, an axially reciprocatable drive rod extending longitudinally of said bed, means for connecting said drive rod to gearing in said apron to effect longitudinal movement of said carriage, feed clutch means between said output shaft of the feed box and the left hand end of said drive rod, and means for engaging said clutch means by the axial movement of said drive rod toward said feed box comprising a trip bar extending longitudinally of the bed of the lathe, means for normally urging said trip bar away from said feed box, means interconnecting said drive rod and said trip bar for opposite reciprocatory movement, means on said trip bar adapted to be actuated during the longitudinal movement of said carriage toward said feed box to effect movement of said drive rod away from said feed box to disengage said feed clutch and arrest longitudinal feeding movement of said carriage, means for connecting or disconnecting said main drive motor relative to said headstock transmission including a spindle control lever having a stop and a run position for the work spindle of said headstock transmission, an interlock mechanism between said spindle lever and said trip bar arranged to hold said trip bar and drive rod in feed disengaged position when said spindle control lever is in stop position, and a 10 yielding connection in said interlock mechanism to allow movement of said spindle control lever to stop position when said trip bar and drive rod are in feed engaged position.

7. In a control mechanism for a lathe having a rotatable work spindle, electric drive means for said work spindle, a cutting tool, first means for moving a cutting tool in longitudinal movement, a second means for moving said cutting tool in transverse movement, an electrical control circuit operable to cause both of said first and second moving means to operate simultaneously to move said cutting tool diagonally relative to the work spindle axis from a starting position to a cutting position, means in said control circuit to stop the in feed movement of the tool toward the work spindle axis while continuing the longitudinal movement of the tool parallel to said axis, mechanical means operated by the longitudinal movement of the tool to a predetermined position to arrest said longitudinal movement and cause said second wardly from said spindle axis to a tool relief position, electric dwell means rendered operative at the beginning of said outward transverse movement of the tool to delay the initiation of a rapid longitudinal return movement of the tool to starting position by said first means until after the completion of said outward transverse movement.

8. In a control mechanism for a lathe having a rotatable Work spindle, electric drive means for said work spindle, a cutting tool, first means for moving a cutting tool in longitudinal movement, a second means, for moving said cutting tool in transverse movement, an electrical control circuit operable to cause both of said first and second means to operate simultaneously to move said cutting tool diagonally relative to the work spindle from a starting position to a cutting position, means in said control circuit to stop the in feed movement of the tool toward the work spindle axis while continuing the longitudinal movement of the tool parallel to said axis, mechanical means operated by the longitudinal movement Of the tool to a predetermined position to arrest said longitudinal movement and cause said second means to move the tool outwardly from said spindle axis to a tool relief position, electric dwell means rendered operative at the beginning of said outward transverse movement of the tool to delay the initiation of a rapid longitudinal return movement of the tool to starting position by said first means until after the completion of said outward transverse movement, and further electrical control means operated by said electrical dwell means to delay the de-energizing 01' said electric drive means for stopping of the rotation of the work spindle until the beginning of said rapid return longitudinal movement of the tool.

9. In a control mechanism for a lathe having a rotatable work spindle, electric drive means for said work spindle, a cutting tool, first means for moving a cutting tool in longitudinal movement, a second means for moving said cutting tool in transverse movement, an electrical control circuit operable to cause both of said first and second means to operate simultaneously to move said cutting tool diagonally relative to the work spindle axis from a starting position to a cutting position, means in said control circuit to stop the in feed movement of the tool toward the work spindle axis while continuing the longitudinal 7 movement of the tool parallel to said axis, me-

means to move the tool outchanical means operated by the longitudinal movement of the tool to a predetermined position to arrest said longitudinal movement and cause said second means to move the tool outwardly from said spindle axis to a tool relief position, electric dwell means rendered operative at the beginning of said outward transverse movement of the tool to delay the initiation of a rapid longitudinal return movement of the tool to starting position by said first means until after the completion of said outward transverse movement, an electrically actuated coolant supply system, and further electrical control means operated by said electrical dwell means to delay through electric circuit means the de-energizing of said electrical drive means for the work spindle and the de-energizing of the electrically actuated coolant supply system until the beginning of said rapid return movement of the cutting tool to starting position.

NELSON D. COOPER.

REFERENCES CITED The following references are of record in the tile of this patent:

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